Architectural shingles, also known as laminated or dimensional shingles, are a popular roofing choice due to their durability and aesthetic appeal. Underlayment is a crucial part of the roofing system, serving as a protective barrier that prevents moisture from penetrating beneath the shingles. For architectural shingles, the most common underlayment is a synthetic or asphalt-saturated felt with a minimum thickness of 15-pound felt or a synthetic equivalent rated for long-term moisture resistance. The reason underlayment is used is to provide secondary protection in case water gets past the shingles during heavy rain or wind-driven storms, and to protect the roof deck from any condensation. A quality underlayment helps ensure the longevity of your roofing system, so if you're inspecting or installing, it’s important to confirm that it meets local building codes and the manufacturer’s warranty conditions.
Homeowners can perform simple DIY checks by looking into the attic for signs of moisture, water stains, or daylight peeking through the roof boards, which might indicate underlayment damage or poor installation. Visually inspecting the roof after storms can help identify any shingles lifting or curling, pointing to potential underlayment or nailing issues. However, underlayment is typically covered by shingles, so if you suspect problems or are replacing a roof, it’s wise to call a professional roofer. When speaking to a contractor, ask specifically, “What type and grade of underlayment do you recommend for architectural shingles here, considering our climate?” and “How do you ensure the underlayment is installed properly to maintain the shingle warranty?” This will help ensure your roofing system is installed right the first time and protected adequately against weather-related damage.